HTML5 is making huge strides toward the semantic web -- and the semantic standards defined by the Google/Bing/Yahoo-backed schema.org are probably prudent standards to follow.
But if we're talking prudence, practicality, and semantics, then we're probably talking CMS too -- not that coding isn't unremitting joy, of course, but there isn't really much point to coding semantics when you're using a CMS to manage content anyway.